Peat is a widely used organic material for agricultural and horticultural applications. Peat is used to improve soil structure, retain moisture, and increase acidity. Peat is also frequently added into agricultural mixes to increase water-holding capacity and/or to decrease weight. Since peat is typically harvested from natural sources such as mires and peat lands, mining of peat presents a threat to fragile peat bog ecosystems by disrupting wildlife habitats and endangering endemic species. Peat lands also contribute to healthy watersheds and aid in providing safe drinking water for human populations. Besides their water filtration capabilities, peat bogs are effective in flood prevention and serve as a very efficient carbon sink. Thus, there is a desire to preserve peat lands and to decrease commercial use of peat.
Various substitutes for peat have been suggested, for example, coir or coconut fiber derived from the husk of the coconut fruit, wood-based substrates, or rice hulls. Yet, all of these substitutes suffer from a variety of drawbacks. For example, neither substitute provides a satisfactory volume of air space. The substitutes also have a relatively high dry and wet bulk density, thus contributing to a relatively high weight of products which include the substitute. Additionally, some of the substitutes may be, just like peat, available only on a limited basis, and their harvesting may have environmental implications.
Accordingly, there is a need for peat replacements that do not negatively impact the environment and which provide desirable properties to a growing medium.